add Math/Trig/Radial.pm, update MANIFEST
[p5sagit/p5-mst-13.2.git] / lib / ExtUtils / Liblist.pm
CommitLineData
005c1a0e 1package ExtUtils::Liblist;
8a1da95f 2use vars qw($VERSION);
005c1a0e 3# Broken out of MakeMaker from version 4.11
4
84902520 5$VERSION = substr q$Revision: 1.25 $, 10;
f1387719 6
005c1a0e 7use Config;
8f1aa56b 8use Cwd 'cwd';
4633a7c4 9use File::Basename;
10
005c1a0e 11sub ext {
3e3baf6d 12 if ($^O eq 'VMS') { return &_vms_ext; }
13 elsif($^O eq 'MSWin32') { return &_win32_ext; }
14 else { return &_unix_os2_ext; }
55497cff 15}
16
17sub _unix_os2_ext {
e611f912 18 my($self,$potential_libs, $verbose) = @_;
f1387719 19 if ($^O =~ 'os2' and $Config{libs}) {
4e68a208 20 # Dynamic libraries are not transitive, so we may need including
21 # the libraries linked against perl.dll again.
22
23 $potential_libs .= " " if $potential_libs;
24 $potential_libs .= $Config{libs};
25 }
4633a7c4 26 return ("", "", "", "") unless $potential_libs;
fb73857a 27 warn "Potential libraries are '$potential_libs':\n" if $verbose;
005c1a0e 28
29 my($so) = $Config{'so'};
30 my($libs) = $Config{'libs'};
55497cff 31 my $Config_libext = $Config{lib_ext} || ".a";
32
005c1a0e 33
34 # compute $extralibs, $bsloadlibs and $ldloadlibs from
35 # $potential_libs
36 # this is a rewrite of Andy Dougherty's extliblist in perl
005c1a0e 37
38 my(@searchpath); # from "-L/path" entries in $potential_libs
39 my(@libpath) = split " ", $Config{'libpth'};
4633a7c4 40 my(@ldloadlibs, @bsloadlibs, @extralibs, @ld_run_path, %ld_run_path_seen);
005c1a0e 41 my($fullname, $thislib, $thispth, @fullname);
8f1aa56b 42 my($pwd) = cwd(); # from Cwd.pm
005c1a0e 43 my($found) = 0;
44
45 foreach $thislib (split ' ', $potential_libs){
46
47 # Handle possible linker path arguments.
48 if ($thislib =~ s/^(-[LR])//){ # save path flag type
49 my($ptype) = $1;
50 unless (-d $thislib){
fb73857a 51 warn "$ptype$thislib ignored, directory does not exist\n"
e611f912 52 if $verbose;
005c1a0e 53 next;
54 }
f1387719 55 unless ($self->file_name_is_absolute($thislib)) {
fb73857a 56 warn "Warning: $ptype$thislib changed to $ptype$pwd/$thislib\n";
f1387719 57 $thislib = $self->catdir($pwd,$thislib);
005c1a0e 58 }
59 push(@searchpath, $thislib);
60 push(@extralibs, "$ptype$thislib");
61 push(@ldloadlibs, "$ptype$thislib");
62 next;
63 }
64
65 # Handle possible library arguments.
66 unless ($thislib =~ s/^-l//){
fb73857a 67 warn "Unrecognized argument in LIBS ignored: '$thislib'\n";
005c1a0e 68 next;
69 }
70
71 my($found_lib)=0;
72 foreach $thispth (@searchpath, @libpath){
73
74 # Try to find the full name of the library. We need this to
75 # determine whether it's a dynamically-loadable library or not.
76 # This tends to be subject to various os-specific quirks.
77 # For gcc-2.6.2 on linux (March 1995), DLD can not load
78 # .sa libraries, with the exception of libm.sa, so we
79 # deliberately skip them.
4e1fac24 80 if (@fullname =
81 $self->lsdir($thispth,"^\Qlib$thislib.$so.\E[0-9]+")){
005c1a0e 82 # Take care that libfoo.so.10 wins against libfoo.so.9.
83 # Compare two libraries to find the most recent version
84 # number. E.g. if you have libfoo.so.9.0.7 and
85 # libfoo.so.10.1, first convert all digits into two
86 # decimal places. Then we'll add ".00" to the shorter
87 # strings so that we're comparing strings of equal length
88 # Thus we'll compare libfoo.so.09.07.00 with
89 # libfoo.so.10.01.00. Some libraries might have letters
90 # in the version. We don't know what they mean, but will
91 # try to skip them gracefully -- we'll set any letter to
92 # '0'. Finally, sort in reverse so we can take the
93 # first element.
94
95 #TODO: iterate through the directory instead of sorting
96
97 $fullname = "$thispth/" .
98 (sort { my($ma) = $a;
99 my($mb) = $b;
100 $ma =~ tr/A-Za-z/0/s;
101 $ma =~ s/\b(\d)\b/0$1/g;
102 $mb =~ tr/A-Za-z/0/s;
103 $mb =~ s/\b(\d)\b/0$1/g;
104 while (length($ma) < length($mb)) { $ma .= ".00"; }
105 while (length($mb) < length($ma)) { $mb .= ".00"; }
106 # Comparison deliberately backwards
107 $mb cmp $ma;} @fullname)[0];
108 } elsif (-f ($fullname="$thispth/lib$thislib.$so")
109 && (($Config{'dlsrc'} ne "dl_dld.xs") || ($thislib eq "m"))){
4633a7c4 110 } elsif (-f ($fullname="$thispth/lib${thislib}_s$Config_libext")
005c1a0e 111 && ($thislib .= "_s") ){ # we must explicitly use _s version
4633a7c4 112 } elsif (-f ($fullname="$thispth/lib$thislib$Config_libext")){
864a5fa8 113 } elsif (-f ($fullname="$thispth/$thislib$Config_libext")){
4633a7c4 114 } elsif (-f ($fullname="$thispth/Slib$thislib$Config_libext")){
8f1aa56b 115 } elsif ($^O eq 'dgux'
c07a80fd 116 && -l ($fullname="$thispth/lib$thislib$Config_libext")
117 && readlink($fullname) =~ /^elink:/) {
118 # Some of DG's libraries look like misconnected symbolic
119 # links, but development tools can follow them. (They
120 # look like this:
121 #
122 # libm.a -> elink:${SDE_PATH:-/usr}/sde/\
123 # ${TARGET_BINARY_INTERFACE:-m88kdgux}/usr/lib/libm.a
124 #
125 # , the compilation tools expand the environment variables.)
005c1a0e 126 } else {
fb73857a 127 warn "$thislib not found in $thispth\n" if $verbose;
005c1a0e 128 next;
129 }
fb73857a 130 warn "'-l$thislib' found at $fullname\n" if $verbose;
4633a7c4 131 my($fullnamedir) = dirname($fullname);
132 push @ld_run_path, $fullnamedir unless $ld_run_path_seen{$fullnamedir}++;
005c1a0e 133 $found++;
134 $found_lib++;
135
136 # Now update library lists
137
138 # what do we know about this library...
4633a7c4 139 my $is_dyna = ($fullname !~ /\Q$Config_libext\E$/);
4e68a208 140 my $in_perl = ($libs =~ /\B-l\Q$ {thislib}\E\b/s);
005c1a0e 141
142 # Do not add it into the list if it is already linked in
143 # with the main perl executable.
974f612f 144 # We have to special-case the NeXT, because math and ndbm
145 # are both in libsys_s
005c1a0e 146 unless ($in_perl ||
974f612f 147 ($Config{'osname'} eq 'next' &&
148 ($thislib eq 'm' || $thislib eq 'ndbm')) ){
005c1a0e 149 push(@extralibs, "-l$thislib");
150 }
151
152 # We might be able to load this archive file dynamically
974f612f 153 if ( ($Config{'dlsrc'} =~ /dl_next/ && $Config{'osvers'} lt '4_0')
154 || ($Config{'dlsrc'} =~ /dl_dld/) )
155 {
005c1a0e 156 # We push -l$thislib instead of $fullname because
157 # it avoids hardwiring a fixed path into the .bs file.
158 # Mkbootstrap will automatically add dl_findfile() to
159 # the .bs file if it sees a name in the -l format.
160 # USE THIS, when dl_findfile() is fixed:
161 # push(@bsloadlibs, "-l$thislib");
162 # OLD USE WAS while checking results against old_extliblist
163 push(@bsloadlibs, "$fullname");
164 } else {
165 if ($is_dyna){
166 # For SunOS4, do not add in this shared library if
167 # it is already linked in the main perl executable
168 push(@ldloadlibs, "-l$thislib")
8f1aa56b 169 unless ($in_perl and $^O eq 'sunos');
005c1a0e 170 } else {
171 push(@ldloadlibs, "-l$thislib");
172 }
173 }
174 last; # found one here so don't bother looking further
175 }
fb73857a 176 warn "Note (probably harmless): "
f3d9a6ba 177 ."No library found for -l$thislib\n"
005c1a0e 178 unless $found_lib>0;
179 }
4633a7c4 180 return ('','','','') unless $found;
181 ("@extralibs", "@bsloadlibs", "@ldloadlibs",join(":",@ld_run_path));
005c1a0e 182}
183
3e3baf6d 184sub _win32_ext {
ecc90c0e 185
186 require Text::ParseWords;
187
e611f912 188 my($self, $potential_libs, $verbose) = @_;
3e3baf6d 189
190 # If user did not supply a list, we punt.
191 # (caller should probably use the list in $Config{libs})
192 return ("", "", "", "") unless $potential_libs;
193
194 my($so) = $Config{'so'};
195 my($libs) = $Config{'libs'};
196 my($libpth) = $Config{'libpth'};
197 my($libext) = $Config{'lib_ext'} || ".lib";
198
199 if ($libs and $potential_libs !~ /:nodefault/i) {
200 # If Config.pm defines a set of default libs, we always
201 # tack them on to the user-supplied list, unless the user
202 # specified :nodefault
203
204 $potential_libs .= " " if $potential_libs;
205 $potential_libs .= $libs;
206 }
fb73857a 207 warn "Potential libraries are '$potential_libs':\n" if $verbose;
3e3baf6d 208
621ba994 209 # normalize to forward slashes
210 $libpth =~ s,\\,/,g;
211 $potential_libs =~ s,\\,/,g;
212
3e3baf6d 213 # compute $extralibs from $potential_libs
214
215 my(@searchpath); # from "-L/path" entries in $potential_libs
ecc90c0e 216 my(@libpath) = Text::ParseWords::quotewords('\s+', 0, $libpth);
3e3baf6d 217 my(@extralibs);
218 my($fullname, $thislib, $thispth);
219 my($pwd) = cwd(); # from Cwd.pm
220 my($lib) = '';
221 my($found) = 0;
222
ecc90c0e 223 foreach $thislib (Text::ParseWords::quotewords('\s+', 0, $potential_libs)){
3e3baf6d 224
225 # Handle possible linker path arguments.
226 if ($thislib =~ s/^-L// and not -d $thislib) {
fb73857a 227 warn "-L$thislib ignored, directory does not exist\n"
e611f912 228 if $verbose;
3e3baf6d 229 next;
230 }
231 elsif (-d $thislib) {
232 unless ($self->file_name_is_absolute($thislib)) {
ecc90c0e 233 warn "Warning: '-L$thislib' changed to '-L$pwd/$thislib'\n";
3e3baf6d 234 $thislib = $self->catdir($pwd,$thislib);
235 }
236 push(@searchpath, $thislib);
237 next;
238 }
239
240 # Handle possible library arguments.
2d7a9237 241 if ($thislib =~ s/^-l// and $thislib !~ /^lib/i) {
242 $thislib = "lib$thislib";
243 }
3e3baf6d 244 $thislib .= $libext if $thislib !~ /\Q$libext\E$/i;
245
246 my($found_lib)=0;
247 foreach $thispth (@searchpath, @libpath){
248 unless (-f ($fullname="$thispth\\$thislib")) {
fb73857a 249 warn "$thislib not found in $thispth\n" if $verbose;
3e3baf6d 250 next;
251 }
fb73857a 252 warn "'$thislib' found at $fullname\n" if $verbose;
3e3baf6d 253 $found++;
254 $found_lib++;
255 push(@extralibs, $fullname);
256 last;
257 }
fb73857a 258 warn "Note (probably harmless): "
3e3baf6d 259 ."No library found for '$thislib'\n"
260 unless $found_lib>0;
261 }
262 return ('','','','') unless $found;
ecc90c0e 263
264 # make sure paths with spaces are properly quoted
265 @extralibs = map { (/\s/ && !/^".*"$/) ? qq["$_"] : $_ } @extralibs;
3e3baf6d 266 $lib = join(' ',@extralibs);
fb73857a 267 warn "Result: $lib\n" if $verbose;
3e3baf6d 268 wantarray ? ($lib, '', $lib, '') : $lib;
269}
270
55497cff 271
272sub _vms_ext {
273 my($self, $potential_libs,$verbose) = @_;
09b7f37c 274 my(@crtls,$crtlstr);
275 my($dbgqual) = $self->{OPTIMIZE} || $Config{'optimize'} ||
276 $self->{CCFLAS} || $Config{'ccflags'};
277 @crtls = ( ($dbgqual =~ m-/Debug-i ? $Config{'dbgprefix'} : '')
278 . 'PerlShr/Share' );
279 push(@crtls, grep { not /\(/ } split /\s+/, $Config{'libs'});
280 push(@crtls, grep { not /\(/ } split /\s+/, $Config{'libc'});
281 # In general, we pass through the basic libraries from %Config unchanged.
282 # The one exception is that if we're building in the Perl source tree, and
283 # a library spec could be resolved via a logical name, we go to some trouble
284 # to insure that the copy in the local tree is used, rather than one to
285 # which a system-wide logical may point.
286 if ($self->{PERL_SRC}) {
287 my($lib,$locspec,$type);
288 foreach $lib (@crtls) {
289 if (($locspec,$type) = $lib =~ m-^([\w$\-]+)(/\w+)?- and $locspec =~ /perl/i) {
290 if (lc $type eq '/share') { $locspec .= $Config{'exe_ext'}; }
291 elsif (lc $type eq '/library') { $locspec .= $Config{'lib_ext'}; }
292 else { $locspec .= $Config{'obj_ext'}; }
293 $locspec = $self->catfile($self->{PERL_SRC},$locspec);
294 $lib = "$locspec$type" if -e $locspec;
295 }
296 }
297 }
298 $crtlstr = @crtls ? join(' ',@crtls) : '';
55497cff 299
09b7f37c 300 unless ($potential_libs) {
301 warn "Result:\n\tEXTRALIBS: \n\tLDLOADLIBS: $crtlstr\n" if $verbose;
302 return ('', '', $crtlstr, '');
303 }
304
305 my(@dirs,@libs,$dir,$lib,%sh,%olb,%obj,$ldlib);
55497cff 306 my $cwd = cwd();
307 my($so,$lib_ext,$obj_ext) = @Config{'so','lib_ext','obj_ext'};
308 # List of common Unix library names and there VMS equivalents
309 # (VMS equivalent of '' indicates that the library is automatially
310 # searched by the linker, and should be skipped here.)
311 my %libmap = ( 'm' => '', 'f77' => '', 'F77' => '', 'V77' => '', 'c' => '',
312 'malloc' => '', 'crypt' => '', 'resolv' => '', 'c_s' => '',
313 'socket' => '', 'X11' => 'DECW$XLIBSHR',
314 'Xt' => 'DECW$XTSHR', 'Xm' => 'DECW$XMLIBSHR',
315 'Xmu' => 'DECW$XMULIBSHR');
316 if ($Config{'vms_cc_type'} ne 'decc') { $libmap{'curses'} = 'VAXCCURSE'; }
317
fb73857a 318 warn "Potential libraries are '$potential_libs'\n" if $verbose;
55497cff 319
320 # First, sort out directories and library names in the input
321 foreach $lib (split ' ',$potential_libs) {
322 push(@dirs,$1), next if $lib =~ /^-L(.*)/;
323 push(@dirs,$lib), next if $lib =~ /[:>\]]$/;
324 push(@dirs,$lib), next if -d $lib;
325 push(@libs,$1), next if $lib =~ /^-l(.*)/;
326 push(@libs,$lib);
327 }
328 push(@dirs,split(' ',$Config{'libpth'}));
329
330 # Now make sure we've got VMS-syntax absolute directory specs
331 # (We don't, however, check whether someone's hidden a relative
332 # path in a logical name.)
333 foreach $dir (@dirs) {
334 unless (-d $dir) {
fb73857a 335 warn "Skipping nonexistent Directory $dir\n" if $verbose > 1;
55497cff 336 $dir = '';
337 next;
338 }
fb73857a 339 warn "Resolving directory $dir\n" if $verbose;
55497cff 340 if ($self->file_name_is_absolute($dir)) { $dir = $self->fixpath($dir,1); }
341 else { $dir = $self->catdir($cwd,$dir); }
342 }
343 @dirs = grep { length($_) } @dirs;
344 unshift(@dirs,''); # Check each $lib without additions first
345
346 LIB: foreach $lib (@libs) {
347 if (exists $libmap{$lib}) {
348 next unless length $libmap{$lib};
349 $lib = $libmap{$lib};
350 }
351
352 my(@variants,$variant,$name,$test,$cand);
353 my($ctype) = '';
354
355 # If we don't have a file type, consider it a possibly abbreviated name and
356 # check for common variants. We try these first to grab libraries before
357 # a like-named executable image (e.g. -lperl resolves to perlshr.exe
358 # before perl.exe).
359 if ($lib !~ /\.[^:>\]]*$/) {
360 push(@variants,"${lib}shr","${lib}rtl","${lib}lib");
361 push(@variants,"lib$lib") if $lib !~ /[:>\]]/;
362 }
363 push(@variants,$lib);
fb73857a 364 warn "Looking for $lib\n" if $verbose;
55497cff 365 foreach $variant (@variants) {
366 foreach $dir (@dirs) {
367 my($type);
368
369 $name = "$dir$variant";
fb73857a 370 warn "\tChecking $name\n" if $verbose > 2;
55497cff 371 if (-f ($test = VMS::Filespec::rmsexpand($name))) {
372 # It's got its own suffix, so we'll have to figure out the type
373 if ($test =~ /(?:$so|exe)$/i) { $type = 'sh'; }
374 elsif ($test =~ /(?:$lib_ext|olb)$/i) { $type = 'olb'; }
375 elsif ($test =~ /(?:$obj_ext|obj)$/i) {
fb73857a 376 warn "Note (probably harmless): "
f3d9a6ba 377 ."Plain object file $test found in library list\n";
55497cff 378 $type = 'obj';
379 }
380 else {
fb73857a 381 warn "Note (probably harmless): "
f3d9a6ba 382 ."Unknown library type for $test; assuming shared\n";
55497cff 383 $type = 'sh';
384 }
385 }
386 elsif (-f ($test = VMS::Filespec::rmsexpand($name,$so)) or
387 -f ($test = VMS::Filespec::rmsexpand($name,'.exe'))) {
388 $type = 'sh';
389 $name = $test unless $test =~ /exe;?\d*$/i;
390 }
391 elsif (not length($ctype) and # If we've got a lib already, don't bother
392 ( -f ($test = VMS::Filespec::rmsexpand($name,$lib_ext)) or
393 -f ($test = VMS::Filespec::rmsexpand($name,'.olb')))) {
394 $type = 'olb';
395 $name = $test unless $test =~ /olb;?\d*$/i;
396 }
397 elsif (not length($ctype) and # If we've got a lib already, don't bother
398 ( -f ($test = VMS::Filespec::rmsexpand($name,$obj_ext)) or
399 -f ($test = VMS::Filespec::rmsexpand($name,'.obj')))) {
fb73857a 400 warn "Note (probably harmless): "
f3d9a6ba 401 ."Plain object file $test found in library list\n";
55497cff 402 $type = 'obj';
403 $name = $test unless $test =~ /obj;?\d*$/i;
404 }
405 if (defined $type) {
406 $ctype = $type; $cand = $name;
407 last if $ctype eq 'sh';
408 }
409 }
410 if ($ctype) {
411 eval '$' . $ctype . "{'$cand'}++";
412 die "Error recording library: $@" if $@;
fb73857a 413 warn "\tFound as $cand (really $test), type $ctype\n" if $verbose > 1;
55497cff 414 next LIB;
415 }
416 }
fb73857a 417 warn "Note (probably harmless): "
f3d9a6ba 418 ."No library found for $lib\n";
55497cff 419 }
420
421 @libs = sort keys %obj;
422 # This has to precede any other CRTLs, so just make it first
423 if ($olb{VAXCCURSE}) {
424 push(@libs,"$olb{VAXCCURSE}/Library");
425 delete $olb{VAXCCURSE};
426 }
427 push(@libs, map { "$_/Library" } sort keys %olb);
428 push(@libs, map { "$_/Share" } sort keys %sh);
429 $lib = join(' ',@libs);
09b7f37c 430
431 $ldlib = $crtlstr ? "$lib $crtlstr" : $lib;
432 warn "Result:\n\tEXTRALIBS: $lib\n\tLDLOADLIBS: $ldlib\n" if $verbose;
433 wantarray ? ($lib, '', $ldlib, '') : $lib;
55497cff 434}
435
005c1a0e 4361;
c2e89b3d 437
864a5fa8 438__END__
cb1a09d0 439
864a5fa8 440=head1 NAME
441
442ExtUtils::Liblist - determine libraries to use and how to use them
443
444=head1 SYNOPSIS
445
446C<require ExtUtils::Liblist;>
447
e611f912 448C<ExtUtils::Liblist::ext($self, $potential_libs, $verbose);>
864a5fa8 449
450=head1 DESCRIPTION
451
452This utility takes a list of libraries in the form C<-llib1 -llib2
453-llib3> and prints out lines suitable for inclusion in an extension
454Makefile. Extra library paths may be included with the form
455C<-L/another/path> this will affect the searches for all subsequent
456libraries.
457
458It returns an array of four scalar values: EXTRALIBS, BSLOADLIBS,
3e3baf6d 459LDLOADLIBS, and LD_RUN_PATH. Some of these don't mean anything
460on VMS and Win32. See the details about those platform specifics
461below.
864a5fa8 462
463Dependent libraries can be linked in one of three ways:
464
465=over 2
466
467=item * For static extensions
468
469by the ld command when the perl binary is linked with the extension
470library. See EXTRALIBS below.
471
472=item * For dynamic extensions
473
474by the ld command when the shared object is built/linked. See
475LDLOADLIBS below.
476
477=item * For dynamic extensions
478
479by the DynaLoader when the shared object is loaded. See BSLOADLIBS
480below.
481
482=back
483
484=head2 EXTRALIBS
485
486List of libraries that need to be linked with when linking a perl
487binary which includes this extension Only those libraries that
488actually exist are included. These are written to a file and used
489when linking perl.
490
491=head2 LDLOADLIBS and LD_RUN_PATH
492
493List of those libraries which can or must be linked into the shared
494library when created using ld. These may be static or dynamic
495libraries. LD_RUN_PATH is a colon separated list of the directories
496in LDLOADLIBS. It is passed as an environment variable to the process
497that links the shared library.
498
499=head2 BSLOADLIBS
500
501List of those libraries that are needed but can be linked in
502dynamically at run time on this platform. SunOS/Solaris does not need
503this because ld records the information (from LDLOADLIBS) into the
504object file. This list is used to create a .bs (bootstrap) file.
505
506=head1 PORTABILITY
507
508This module deals with a lot of system dependencies and has quite a
509few architecture specific B<if>s in the code.
510
55497cff 511=head2 VMS implementation
512
513The version of ext() which is executed under VMS differs from the
514Unix-OS/2 version in several respects:
515
516=over 2
517
518=item *
519
520Input library and path specifications are accepted with or without the
521C<-l> and C<-L> prefices used by Unix linkers. If neither prefix is
522present, a token is considered a directory to search if it is in fact
523a directory, and a library to search for otherwise. Authors who wish
524their extensions to be portable to Unix or OS/2 should use the Unix
525prefixes, since the Unix-OS/2 version of ext() requires them.
526
527=item *
528
529Wherever possible, shareable images are preferred to object libraries,
530and object libraries to plain object files. In accordance with VMS
531naming conventions, ext() looks for files named I<lib>shr and I<lib>rtl;
532it also looks for I<lib>lib and libI<lib> to accomodate Unix conventions
533used in some ported software.
534
535=item *
536
537For each library that is found, an appropriate directive for a linker options
538file is generated. The return values are space-separated strings of
539these directives, rather than elements used on the linker command line.
540
541=item *
542
09b7f37c 543LDLOADLIBS contains both the libraries found based on C<$potential_libs> and
544the CRTLs, if any, specified in Config.pm. EXTRALIBS contains just those
545libraries found based on C<$potential_libs>. BSLOADLIBS and LD_RUN_PATH
546are always empty.
55497cff 547
548=back
549
550In addition, an attempt is made to recognize several common Unix library
551names, and filter them out or convert them to their VMS equivalents, as
552appropriate.
553
554In general, the VMS version of ext() should properly handle input from
555extensions originally designed for a Unix or VMS environment. If you
556encounter problems, or discover cases where the search could be improved,
557please let us know.
558
3e3baf6d 559=head2 Win32 implementation
560
561The version of ext() which is executed under Win32 differs from the
562Unix-OS/2 version in several respects:
563
564=over 2
565
566=item *
567
568Input library and path specifications are accepted with or without the
569C<-l> and C<-L> prefices used by Unix linkers. C<-lfoo> specifies the
2d7a9237 570library C<libfoo.lib> (unless C<foo> already starts with C<lib>), and
571C<-Ls:ome\dir> specifies a directory to look for the libraries that follow.
572If neither prefix is present, a token is considered a directory to search
573if it is in fact a directory, and a library to search for otherwise. The
574C<$Config{lib_ext}> suffix will be appended to any entries that are not
575directories and don't already have the suffix. Authors who wish their
576extensions to be portable to Unix or OS/2 should use the Unix prefixes,
577since the Unix-OS/2 version of ext() requires them.
3e3baf6d 578
579=item *
580
581Entries cannot be plain object files, as many Win32 compilers will
582not handle object files in the place of libraries.
583
584=item *
585
586If C<$potential_libs> is empty, the return value will be empty.
587Otherwise, the libraries specified by C<$Config{libs}> (see Config.pm)
588will be appended to the list of C<$potential_libs>. The libraries
589will be searched for in the directories specified in C<$potential_libs>
590as well as in C<$Config{libpth}>. For each library that is found, a
591space-separated list of fully qualified library pathnames is generated.
592You may specify an entry that matches C</:nodefault/i> in
593C<$potential_libs> to disable the appending of default libraries
594found in C<$Config{libs}> (this should be only needed very rarely).
595
596=item *
597
598The libraries specified may be a mixture of static libraries and
599import libraries (to link with DLLs). Since both kinds are used
600pretty transparently on the win32 platform, we do not attempt to
601distinguish between them.
602
603=item *
604
605LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS
606and LD_RUN_PATH are always empty (this may change in future).
607
ecc90c0e 608=item *
609
610You must make sure that any paths and path components are properly
611surrounded with double-quotes if they contain spaces. For example,
612C<$potential_libs> could be (literally):
613
614 "-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib"
615
616Note how the first and last entries are protected by quotes in order
617to protect the spaces.
618
3e3baf6d 619=back
620
621
864a5fa8 622=head1 SEE ALSO
623
624L<ExtUtils::MakeMaker>
625
626=cut
627